Automatic control for mining pit props

ABSTRACT

A control for the alignment and if need be, pivoting of a prop or post in mining, whose theoretical course in the plane of the work is indicated by a straight line or a curve and whose ideal or actual course results from positive or negative deviations, which are analyzed at several measuring points located along the prop or post by means of digital forward and backward (or positive and negative) logic pulses. Each measuring point corresponds to an evaluation unit having a storage member. Each unit converts the stored signals into control signals for spatially differentiated treatment of a mine face, whereby the storage members of the evaluation units are connected with one another by a storage interrogation and return conduit. To each measuring point are assigned two measuring devices, of which at least one comprises a thrust-piston drive serving for the advance of the recovery device. The piston path or stroke of the thrust piston drive is divided into partial lengths, whose throughpassage through the piston in each case releases one of the binary rearward or forward pulses.

United States Patent [19] Schmidt 11] 3,754,129 [4 1 Aug. 21, 1973 1 AUTOMATIC CONTROL FOR MINING PIT PROPS [75] Inventor: Helmut Schmidt, Essen-Haarzopf,

Germany [73] Assignee: Bergwerksverband GmbH,

Essen-Kray, Germany [22] Filed: Aug. 5, 1970 [21] App]. No.: 61,345

[30] Foreign Application Priority Data Aug. 6, 1969 Germany P 19 39 990.7

[52] US. Cl. 235/201, 61/45 D [51] Int. Cl. G06m 1/12 [58] Field of Search 61/45 D; 235/151.3,

235/151.32, 151, 201R, 201 ME, 201 FS, 201 PF, 200 R;91/l, 189, 36, 363,411, 412, 413, 414,170 MP; 299/11, 31, 33

[56] References Cited UNITED STATES PATENTS 3,224,674 12/1965 Warren 235/201 R 3,319,644 5/1967 Thorburn 235/201 ME X 3,436,922 4/1969 lrresberger et a]. 91/1 X 3,437,010 4/1969 Jacobi et al 91/1 X 3,445,640 5/1969 Harrison et a1. 235/151.32 3,452,645 7/1969 Barltrop 91/1 X 3,478,522 11/1969 Rieschel 9l/1 X 3,473,546 10/1969 Bellman 235/201 PF X 3,495,499 2/1970 Ward 91/1 s P 1 l 3,495,776 2/1970 ONeil1.... 235/201 PF 3,534,560 10/1970 Rieschel 61/45 D 3,531,800 9/1970 Brescia 235/15l.32 UX 3,537,102 10/1970 Baratto 235/151.32 UX 3,482,877 12/1969 Jacobi 61/45 D X Primary Examiner-Dennis L. Taylor Attorney-Malcolm W. Fraser [5 7] ABSTRACT A control for the alignment and if need be, pivoting of a prop or post in mining, whose theoretical course in the plane of the work is indicated by a straight line or a curve and whose ideal or actual course results from positive or negative deviations, which are analyzed at several measuring points located along the prop or post by means of digital forward and backward (or positive and negative) logic pulses. Each measuring point corresponds to an evaluation unit having a storage member.

' Each unit converts the stored signals into control signals for spatially differentiated treatment of a mine face, whereby the storage members of the evaluation units are connected with one another by a storage interrogation and return conduit. To each measuring point are assigned two measuring devices, of which at least one comprises a thrust-piston drive serving for the advance of the recovery device-The piston path or stroke of the thrust piston drive is divided into partial lengths, whose through-passage through the piston in each case releases one of the binary rearward or forward pulses.

3 Claims, 4 Drawing Figures Patented Aug. 21, 1973 3,754,129

2 Sheets-Sheet 1 lgENToR. QZMMAQM mama-n} Patented Aug. 21, 1973 I 3,754,129

2 Sheets-Sheet :3

F IGA RS R v U0 U0 [L10 b t 5% y 2o JUVL i INVENTOR AYE Z' WW7 AUTOMATIC CONTROL FOR MINING PIT PROPS BACKGROUND OF THE INVENTION I The device according to U.S. Pat. No. 3,531,159 renders possible the continuous detection of the actual course of a mining prop or post and the correction of the course of the prop or post according to a theoreticalof ideal value, whereby through introduction of corresponding control, a pivoting of the prop or post may be carried out according to plan. The control is based upon the theoretical course which extends through the location of a recovery device lying further back, which may be for example, a conveyor (such as conveyor 2 in said U.S. Pat. No. 3,531,159 as only then do all thrust-piston drives portray the deviation correctly. On the other hand, it frequently can not be prevented, that the parts of the recovery device which are advanced for measuring occasionally fall behind. This is frequently the case if the thrust-piston drives utilized for the forward pressing are relieved of load and advanced. The falling behind would however, result in a shifting of the reference point from which the forward and rearward pulses of the measuring device are counted. This again would lead to errors in the guidance.

The device according to the above U.S. Patent attempts to eliminate this problem by providing at each measuring point, two devices which are formed by two adjacent thrust-piston drives. The measuring may thereby always be carried out by that thrust-piston drive which is braced straight, while the other thrustpiston drive is advanced. This solution has, however, several disadvantages.

Upon change over, an error of plus or minus one digital unit may occur. These errors may accumulate and thereby multiply. In such case, the guidance no longer operates satisfactorily and must be corrected. In addition, the change over can not always be carried out automatically. Then further errors result, if the change over is not carried out correctly.

SUMMARY OF THE INVENTION serves for the advance of the recovery device and a rear thrust piston drive measures the spacing of the supports of the two thrust piston drives, and that the evaluation unit receives the sum of the measurements of both thrust-piston drives.

With such guidance, the removal of the load of the front thrust-piston drive and its advancement causes a corresponding number of rearward pulses. These pulses are multiplied by a series of'additional rearward pulses, when the recovery device slides backwards. Because, at the same time, the spacing of the two supports is increased, the rear thrust-piston drive delivers a number of forward impulses corresponding to the advancing movement of the forward thrust-piston drive. The algebraic sum of all pulses is supplied by the rearward movement of the recovery device, which is to be corrected by means of the guidance.

Such guidance has the advantage that it detects with certainty solely the changes in position of the recovery device. In addition, for this purpose, only half of the thrust-piston drives used in the control according to the U.S'. Pat. No. 3,531,159 are necessary, because the rear thrust-piston drive does not serve to advance the recovery device.

The measuring device of the rearward thrust-piston drive, which serves exclusively for the measuring, is disconnected upon advancing its support. This thrustpiston drive may be constructed relatively simply. A pneumatically impinged thrust-piston drive is sufficient for this purpose, when the front thrust-piston drive is actuated hydraulically.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows diagrammatically a measuring point before advancing the measuring thrust-piston drive;

FIG. 2 shows a view corresponding to FIG. 1 with the parts in the condition after advancement;

FIG. 3 shows the condition of the parts, after the support of the second thrust-piston drive is also advanced; and

FIG. 4 is a hydraulic logic circuit according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. I, a pivot F of a conveyor is connected to a hydraulic thrust-piston drive H. A part of a recovery device is shown connected to the pivot. The hydraulic thrust-piston drive H is supported at S 2. The support may be carried out by means of a hydraulic post or in any other manner desired. The support S 2 is itself connected with a further thrust-piston drive P, whose support is located at S l.

Both thrust-piston drives M1 and M2 are provided with devices which are in position to measure the partial lengths passed through in each case by the piston rods. This measurement may, for example, be made with the aid of a perforated disc, which is rotated synchronously with the movement of the piston rods, and which controls an air current. In this manner, the thrust-piston drivesmay supply forward and rearward pulses, which are introduced into an evaluation unit E as the sum of the measurements, in order to measure the deviations of the actual course of the conveyor from the theoretical course. Elements M1, M2 and E are illustrated only in FIG. I, but would also be found in the systems of FIGS. 2 and 3.

Upon advancement of the front and preferably hydraulically actuated thrust-piston drive H, the support S 2 is released and follows up toward pivot F. Itis assumed for this discussion that the length of the path of the piston rod is divided into five digital units. The mea- With the shifting of the support S 2, however, at the same time the piston rod of the rearward thrust-piston drive P is advanced. The measuring device associated with this thrust-piston drive produces thereby a series whereby, at the control 2, rearward pulses are given off. These rearward pulses indicate accurately the change in position of the conveyor.

The advancement of the support S 2 may accordingly take place at any desired point of time and any desired manner, without measurement errors occurring in the control. If subsequently the point S l is drawn up in the direction toward S 2, then the rearward thrust-piston drive P is automatically disconnected and supplies no rearward pulses.

The rearward thrust-piston drive may be actuated pneumatically, even if the front thrust-piston drive H is hydraulically driven because of the large forces applied by it.

The hydraulic logic circuit shown in FIG. 4 operates in cycles.

The forward pulses appearing at V, the rearward pulses occurring at R and the rear wetting pulses occurring at RS may therefore be of any desired form and duration of time. In this manner, pulse fonners are eliminated, whose capillaries are known to be subject to disturbance.

The RS, R and V pulses may have any desired duration and form and may also occur at desired points of time, accordingly even simultaneously. They are stored in reset-dominated storage members 10, and 30. A sufficiently rapid pulse generator paces the AND members 100, 200 and 300 so that RS and R pulses are permitted to pass solely during the pulse duration of the cycle pulses, while V pulses are passed on solely in the pulse pause of the cycle. Thereby, the V pulses are automatically locked against the R and RS pulses. The locking between RS and R pulses takes place by means of the locking conduits V200 or V100 and 100 and 200. Accordingly, the first pulse occurring is also treated first.

The AND gates 100 and 200 are in each case opened for the duration of a cycle pulse, so that the rearward shifting pulses reaching the storage register through the OR gate 40, are not longer than the cycle pulse. Likewise, the forward pulses reaching the shifting register at 50 are not longer than the pause or interruption in the cycle.

If a pulse passes an AND gate 100, 200 or 300, respectively, then the associated and pre-connected storage member 11, 21 or 31, respectively, is set. Thereby the AND members 1 11, and 21 1 take care that the correct storage member is set by the pulse at 40.

The storage member 11, 21 or 31 resets the respectively associated storage members 10, 20 or 30. On account of the reset domination, a re-connection of these storage members by means of still existing R, RS or V pulses is not possible, as long as the respectively correlated storage member 11, 21 or 31 still carries a signal.

The resetting of the storage member 11, 21 or 31 takes place through the respective AND gates 110, 210 or 310 when first the respective signal RS, R or V, has disappeared, and when secondly the associated storage member 10, 20 or 30 in each case has been reset.

The signals retained in the storage members are now converted into control signals, which make possible a spatially differentiated treatment of the face of the mine.

It is also possible for the combination of the two pneumatic measuring cylinders H and P to be used as purely measuring system for other purposes.

What I claim is:

1. In a system for use in advancing equipment at a mine face in order to reduce the deviation between an actual position of said equipment and a theoretical desired position, an improved measurement system for digitally measuring a distance through which at least a portion of said equipment is advanced, comprising:

A. a first thrust-piston drive (H) having a piston thrust path divided into a plurality of partial lengths and being connected to advance said equipment (F) with respect to a first support point (S2),

B. first measurement means for providing a first train of pulses having a number equal to the number of said partial lengths traversed by said first thrustpiston drive and having a forward or rearward characteristic determined by the direction advance of said first thrust-piston drive,

C. a second thrust-piston drive having a piston thrust path divided into a plurality of similar partial lengths and being connected to advance said first support point (S2) with respect to a second support point (81),

D. second measurement means for providing a second train of pulses having a number equal to the number of partial lengths corresponding to the change in displacement between the first and second support points and having a forward or rearward characteristic determined by the direction of said change of displacement, and

E. means for evaluating the algebraic sum of the first and second trains of pulses for digitally measuring the distance through which said equipment is advanced.

2. A system according to claim 1 wherein the second measurement means is controlled to prevent it from generating pulses during a period when the second support point is being advanced.

3. A system according to claim 1 wherein the first thrust-piston drive is actuated hydraulically and the second thrust-piston drive is actuated pneumatically. 

1. In a system for use in advancing equipment at a Mine face in order to reduce the deviation between an actual position of said equipment and a theoretical desired position, an improved measurement system for digitally measuring a distance through which at least a portion of said equipment is advanced, comprising: A. a first thrust-piston drive (H) having a piston thrust path divided into a plurality of partial lengths and being connected to advance said equipment (F) with respect to a first support point (S2), B. first measurement means for providing a first train of pulses having a number equal to the number of said partial lengths traversed by said first thrust-piston drive and having a forward or rearward characteristic determined by the direction advance of said first thrust-piston drive, C. a second thrust-piston drive having a piston thrust path divided into a plurality of similar partial lengths and being connected to advance said first support point (S2) with respect to a second support point (S1), D. second measurement means for providing a second train of pulses having a number equal to the number of partial lengths corresponding to the change in displacement between the first and second support points and having a forward or rearward characteristic determined by the direction of said change of displacement, and E. means for evaluating the algebraic sum of the first and second trains of pulses for digitally measuring the distance through which said equipment is advanced.
 2. A system according to claim 1 wherein the second measurement means is controlled to prevent it from generating pulses during a period when the second support point is being advanced.
 3. A system according to claim 1 wherein the first thrust-piston drive is actuated hydraulically and the second thrust-piston drive is actuated pneumatically. 